LESSONS LEARNED FROM CARBON NANOTUBE GROWTH CAN BE APPLIED TO GRAPHENE: 100% REPRODUCIBILITY AND IMPROVED GRAPHENE QUALITY BY PREHEATING PRECURSOR GASES USING THERMAL CHEMICAL VAPOR DEPOSITION

Years ago, we showed how preheating precursor gases helped to synthesize carbon nanotubes (CNTs) at lower temperature and with increased crystallinity. We recently demonstrated how by applying a similar technique, we synthesized high quality, few-layer graphene at reduced temperature with full reproducibility on nickel thin films.

Raman spectroscopy showed that the graphene films synthesized using gas preheating exhibited 50% less defects compared to those obtained without gas preheating. However, the most important outcome is that all experiments performed using gas preheating were fully reproducible, while less than 15% of the experiments performed without gas preheating led to graphene of only acceptable quality. Gas chromatography/mass spectrometry (GC-MS) of the preheated gases showed an increased formation of polycyclic aromatic hydrocarbons (PAHs), as it did in our previous studies on CNTs.

From the results obtained, we postulated a new growth mechanism that fits previous density functional theory (DFT) reports of hydrocarbon stability on a nickel surface. The results presented are an important step in the direction of graphene synthesis at lower temperatures with full reproducibility. In this presentation, we will focus on the parallels between CNT and graphene synthesis and discuss how other insights on CNT growth could be leveraged to improve graphene synthesis.

This work has been published in the Journal of Materials Chemistry A (M. Somekh, et al., Fully reproducible, low-temperature synthesis of high-quality, few-layer graphene on nickel via preheating of gas precursors using atmospheric pressure chemical vapor deposition, Journal of Materials Chemistry A, P.19750-19758, Issue 36, December 2014).